1. Field of the Invention
The invention is concerned with amorphous metal alloys and, more particularly, with amorphous metal alloys which include iron or cobalt plus boron.
2. Description of the Prior Art
Novel amorphous metal alloys have been disclosed and claimed by H. S. Chen and D. E. Polk in U.S. Pat. No. 3,856,513, issued Dec. 24, 1974. These amorphous alloys have the formula M.sub.a Y.sub.b Z.sub.c, where M is at least one metal selected from the group consisting of iron, nickel, cobalt, chromium and vanadium, Y is at least one element selected from the group consisting of phosphorus, boron and carbon, Z is at least one element selected from the group consisting of aluminum, antimony, beryllium, germanium, indium, tin and silicon, a ranges from about 60 to 90 atom percent, b ranges from about 10 to 30 atom percent and c ranges from about 0.1 to 15 atom percent. These amorphous alloys have been found suitable for a wide variety of applications, including ribbon, sheet, wire, powder, etc. Amorphous alloys are also disclosed and claimed having the formula T.sub.i X.sub.j, where T is at least one transition metal, X is at least one element selected from the group consisting of aluminum, antimony, beryllium, boron, germanium, carbon, indium, phosphorus, silicon at tin, i ranges from about 70 to 87 atom percent and j ranges from about 13 to 30 atom percent. These amorphous alloys have been found suitable for wire applications.
At the time these amorphous alloys were discovered, they evidenced mechanical properties that were superior to then-known polycrystalline alloys. Such superior mechanical properties included ultimate tensile strengths up to 350,000 psi, hardness values of about 600 to 750 DPH and good ductility. Nevertheless, new applications requiring improved magnetic, physical and mechanical properties and higher thermal stability have necessitated efforts to develop further specific compositions.
With regard to methods of preparation, two general methods exist for preparing the amorphous metal alloys. The first method consists of procedures wherein atoms are added to an aggregate essentially one atom at a time. Such deposition procedures include vapor deposition, electrodeposition, chemical (electroless) deposition and sputtering.
The second method consists of procedures involving rapid quenching of a melt. Examples of such procedures include the various well-known "splat" techniques and continuous quenching techniques such as disclosed by J. Bedell in U.S. Pat. Nos. 3,862,658 and 3,863,700 and by S. Kavesh in U.S. Pat. No. 3,881,540. This second method is generally limited to materials which may be quenched to the amorphous state at rates less than about 10.sup.10 .degree. C./sec and more usually at rates of about 10.sup.5 to 10.sup.6 .degree. C./sec, which are attainable in presently available apparatus. The first method is more broadly applicable to all classes of metallic materials.
It has been suggested that a high degree of compositional complexity is essential in order to form amorphous metal alloys by quenching from the melt. See, e.g., B. C. Giessen and C. N. J. Wagner, "Structure and Properties of Noncrystalline Metallic Alloys Produced by Rapid Quenching of Liquid Alloys," in Liquid Metals-Chemistry and Physics, S. Z. Beer, Ed., pp. 633-695, Marcel Dekker Inc., New York (1972) and D. Turnbull, Vol. 35, Journale de Physique, Colloque-4, pp. C4-1 - C4-10, 1974.
While some particular binary alloys of iron group metals have been made amorphous by some of the deposition methods, binary amorphous iron group alloys have not been reported by quenching form the melt.